This article deals with an experimental study on the aerodynamic characteristics of a low-drag high-speed nature laminar flow (NLF) airfoil for business airplanes in the TST27 wind tunnel at Delft University of Techno...This article deals with an experimental study on the aerodynamic characteristics of a low-drag high-speed nature laminar flow (NLF) airfoil for business airplanes in the TST27 wind tunnel at Delft University of Technology, the Netherlands. In this experiment, in an attempt to reduce the errors of measurement and improve its accuracy in high-speed flight, some nonintrusive meas- urement techniques, such as the quantitative infrared thermography (IRT), the digital particle imaging velocimetry (PIV), and the s...展开更多
The inner flow analysis of centrifugal pumps has gradually become an important issue for the hydraulic design and performance improvement.Nowadays,CFD simulation toolbox of pump inner flow mainly contains commercial t...The inner flow analysis of centrifugal pumps has gradually become an important issue for the hydraulic design and performance improvement.Nowadays,CFD simulation toolbox of pump inner flow mainly contains commercial tools and open source tools.There are some defects for commercial CFD software for the numerical simulation of 3-D turbulent internal flow in pump,especially in capturing the flow characteristics under the off-design operating conditions.Additionally,it is difficult for researchers to do further investigation because of the undeclared source.Therefore,an open source software like Open Field Operation and Manipulation （OpenFOAM） is increasingly popular with researchers from all over the world.In this paper,a new computational study was implemented based on the original solver and was used to directly simulate the steady-state inner flow in a double blades pump,with the specific speed is 111.In order to disclose the characteristics deeply,three research schemes were conducted.The ratios （） of the flow rate are 0.8,1.0 and 1.2,respectively.The simulation results were verified with the Particle Imaging Velocimetry （PIV） experimental results,and the numerical calculation results agree well with the experimental data.Meanwhile,the phenomena of flow separation under the off-design operating conditions are well captured by OpenFOAM.The results indicate that OpenFOAM possesses obvious strong predominance in computing the internal flow field of pump.The analysis results can also be used as the basis for the further research and the improvement of centrifugal pump.展开更多
Particle Imaging Velocimetry (PIV) is a valuable measuring tool for studyingmultiphase flows, such as liquid-gas and gas-solid flow. It can be used to carry out manyhydrodynamic studies, in particular, to determine ac...Particle Imaging Velocimetry (PIV) is a valuable measuring tool for studyingmultiphase flows, such as liquid-gas and gas-solid flow. It can be used to carry out manyhydrodynamic studies, in particular, to determine accurately the gas solid flow structure in CFB(Circulating Fluidized Beds). In this paper, the technique characteristics was described in applyingthe PIV to measure the gas-solid flow in circulating fluidized beds. A primary experiment wascomple-ted on a CFB unit with the PIV, yielding the velocity vector fields of high-density particlesfor different gas-solid superficial velocities and solid recycle rates. Velocities of thetransported particles were calculated with cross-correlation method. The major factors influencingthe successful measurement of particle velocity with the PIV technique were also described.展开更多
文摘This article deals with an experimental study on the aerodynamic characteristics of a low-drag high-speed nature laminar flow (NLF) airfoil for business airplanes in the TST27 wind tunnel at Delft University of Technology, the Netherlands. In this experiment, in an attempt to reduce the errors of measurement and improve its accuracy in high-speed flight, some nonintrusive meas- urement techniques, such as the quantitative infrared thermography (IRT), the digital particle imaging velocimetry (PIV), and the s...
基金Project supported by the National Natural Science Funds for Distinguished Young Scholar (Grant No.50825902)the National Natural Science Foundation of China (Grant Nos.51079062,51179075 and 51109095)the Natural Science Foundation of Jiangsu Province (Grant Nos.BK2009006,BK2010346)
文摘The inner flow analysis of centrifugal pumps has gradually become an important issue for the hydraulic design and performance improvement.Nowadays,CFD simulation toolbox of pump inner flow mainly contains commercial tools and open source tools.There are some defects for commercial CFD software for the numerical simulation of 3-D turbulent internal flow in pump,especially in capturing the flow characteristics under the off-design operating conditions.Additionally,it is difficult for researchers to do further investigation because of the undeclared source.Therefore,an open source software like Open Field Operation and Manipulation （OpenFOAM） is increasingly popular with researchers from all over the world.In this paper,a new computational study was implemented based on the original solver and was used to directly simulate the steady-state inner flow in a double blades pump,with the specific speed is 111.In order to disclose the characteristics deeply,three research schemes were conducted.The ratios （） of the flow rate are 0.8,1.0 and 1.2,respectively.The simulation results were verified with the Particle Imaging Velocimetry （PIV） experimental results,and the numerical calculation results agree well with the experimental data.Meanwhile,the phenomena of flow separation under the off-design operating conditions are well captured by OpenFOAM.The results indicate that OpenFOAM possesses obvious strong predominance in computing the internal flow field of pump.The analysis results can also be used as the basis for the further research and the improvement of centrifugal pump.
文摘Particle Imaging Velocimetry (PIV) is a valuable measuring tool for studyingmultiphase flows, such as liquid-gas and gas-solid flow. It can be used to carry out manyhydrodynamic studies, in particular, to determine accurately the gas solid flow structure in CFB(Circulating Fluidized Beds). In this paper, the technique characteristics was described in applyingthe PIV to measure the gas-solid flow in circulating fluidized beds. A primary experiment wascomple-ted on a CFB unit with the PIV, yielding the velocity vector fields of high-density particlesfor different gas-solid superficial velocities and solid recycle rates. Velocities of thetransported particles were calculated with cross-correlation method. The major factors influencingthe successful measurement of particle velocity with the PIV technique were also described.
